When newly hatched haddock (Melanogrammus aeglefinus) larvae were fed zooplankters at nominal rates of 0.5, 1.0, and 3.0/ml in the laboratory at 7 C, they grew at similar rates. After 6 wk, they averaged 8.7, 10.0, and 11.2 mm in standard length and 810, 1300, and 1728 μg in dry weight, and had condition factors of 1.25, 1.22, and 1.32. When fed at 0.1 and 0.01 plankters/ml, all larvae died in 3 and 2 wk; at 0.5-3.0 plankters/ml, daily instantaneous mortality coefficients were 0.06–0.02 during 6 wk. Larvae began feeding 2 days after hatching, and the point of no return after they were deprived of food was 6 days after hatching, yolk absorption being completed on day 6 or 7. All larvae deprived of food until 8 and 10 days after hatching, although initiating feeding, did not survive another 4 days. Prey concentration also influenced delayed feeding with greater percentages of larvae able to initiate feeding at higher plankton levels on the point-of-no-return day.